 The major classification systems for use in the United States include the National Fire Danger Rating System, the 13 ‘original’ fuel models of Anderson and Albini, the subsequent set of 40 fuels produced by Scott and Burgan, and the Fuel Characteristics Classification System.The concept of a fuel model was first introduced in 1972 with the National Fire Danger Rating System.The first system of its kind, the NFDRS was a standardized set of equations to determine fire danger at specific points on the landscape.